Ovarian cancer is the most lethal gynecologic malignancy. This largely reflects the fact that approximately 75% of cases are detected at advanced stages of disease, when cure is unlikely. In contrast, 5-year survival for patients with early stage ovarian cancer can exceed 90%. It is possible therefore that detecting a greater number of patients with early stage disease by improving screening modalities could significantly improve overall survival.
To date, detection of the tumor marker CA 125 secreted from ovarian epithelium is the only biomarker available for screening. Detection of CA 125 antigen is based on ELISA and RIA assays used in serologic screening for ovarian cancer and monitoring patient therapeutic responses. However, the sensitivity of the current methods is approximately 70%, thereby greatly limiting its value in mass screening for the disease.
Lung cancer continues to be the most lethal malignancy, accounting for an estimated 160,000 deaths per year in the United States. This high mortality reflects the fact that the majority of cases are detected at advanced stages, when cure is unlikely. At the same time lung cancer is one of the most ‘avoidable’ causes of death worldwide. It is also one in which differences in relation to sex and gender especially significant. Increasing lung cancer deaths amongst women alongside stable or decreasing deaths amongst men in many countries have substantially altered the male:female ratio in this disease and produced a need to understand differences between men and women in lung cancer risk, and how they relate to sex and gender. The risk of lung cancer may be different for men and women in response to a complex interaction between biological factors such as hormonal difference and gendered factors such as smoking behavior. Women's apparently greater relative risk of lung cancer and the differences between men and women in the risk of specific histological types of lung cancer need to be understood from a perspective in which both biological influences and gender influences are drawn out.
Shifting detection to an early stage could significantly improve overall survival. Molecular methods, including application of sensitive and specific lung cancer biomarkers, are a promising strategy to achieve this goal. We propose a novel approach to increase the accuracy of early lung cancer detection through the application of nanotechnology, where lung cancer biomarkers, biochemically conjugated to fluorescent semiconductor nanocrystals called “quantum dots” (QD) are detected by a unique QD-immunometric methodology utilizing photoluminescence spectroscopy (PL).
Quantum Dots (QD) have attracted a great attention from the medicine/biology because of the advantages they offer over conventional organic dyes. Nanometer-sized semiconductor particles have been covalently linked to biorecognition molecules, i.e., antibodies, peptides, nucleic acids, or molecular ligands for application as fluorescent probes. Compared to organic dyes, quantum dots have unique optical and electronic properties, such as size- and composition-tunable fluorescence emission from visible to infrared wavelengths, large absorption coefficients across a wide spectral range and high levels of brightness and photostability. High-quality QDs were described recently in efficient optical multiplexing for in vivo cancer imaging using animal models. It was shown that biological tissues can be filters, which decrease QDs' absorbance at bluer wavelengths. Multicolor optical coding for oligonucleotides assay has been achieved by embedding different-sized QDs into polymeric microbeads. The use of ten intensity levels and six colors is supposed theoretically to code a million nucleic acid or protein sequences that can be developed for medical diagnostics. Bioconjugation of Quantum Dotes (QDs) involves the attachment of specific ligands, and represents the convolution of biotechnology and nanotechnology yielding hybrid materials, processes and devices.
Therefore, what is needed is a novel approach to increase the sensitivity and specificity of early detection of cancer through the application of nanotechnology, where luminescent semiconductor quantum dots (QDs) are conjugated with biomolecules.